Need advice on balancing my tank to remove GSA & Staghorn Algae!

[meyscapes]

Hello!

I have a Dennerle 35 Scapers tank that has been running since September 2021 and it’s my first high tech setup with a Chihiros WRGB2 and pressurised Co2 system. I previously had the light set up at 50-60% intensity for 6 hours a day, but a couple of months ago I increased this to 8 hours as the tank was more established and the plants were doing well, so I thought this would improve their growth even more. This caused GSA to start appearing on the rocks at quite a fast rate and so I recently reduced the lighting intensity down to 40-50%, still for 8 hours a day.

Before this change the plants were doing great and growing really well, but in the last couple of weeks I’ve noticed a big slow down in their growth rate. On top of this the GSA is still there and I’m now also starting to get staghorn algae on the plants!

Today I calculated my Co2 levels using PH and KH and I discovered that my Co2 level is actually higher than it should be. I’ve always had a drop checker in the tank which reads as light green and so I assumed this was good, but when I did the KH and PH tests, my KH read as 4.5-5 and my PH was 6.6, resulting in a Co2 level of around 30-37ppm.

Almost all of my plants are classed as “Medium” by the Tropica website and so I was wondering if I should either:

1. Reduce the Co2 amount first as they naturally require less and this could also match my newer lower lighting intensity?

And/Or

2: Just go back to 50-60% lighting intensity for 6 hours a day as from what I remember this seemed to have the best plant growth.

Then again, I’m not sure if the initial fast plant growth was because the setup was newer and so there were maybe more ferts available for the plants in the soil, as it is the ADA Amazonia soil. The only other ferts I’ve been adding to the tank is a daily dose of 2hr aquarist apt zero.

Either way, with all of the variables between lighting, Co2 and ferts I’m a bit overwhelmed on how best to solve this or where even to start 😅

Any help or advice would be very much appreciated, thank you!

 

[MichaelJ]

Hi @meyscapes Welcome to UKAPS

I am not a CO2 expert, but your algae issues may stem from faulty CO2 application (amount/flow etc.) vs. light intensity vs. fertilizer. You may want to do a pH profile. In addition, it may be helpful to post a full tank shot so we can see what's going on in your tank vs. algae, plant mass, drop checker etc.

Cheers,
Michael

 

[plantnoobdude]

plants classed as 'medium' will still benefit from more co2. 30-37ppm is fine.. but the reality is you probably have much less. ph kh charts are quite inaccurate and i'd trust your drop checker more. just make sure you're placing it correctly. it should be placed in an area that co2 bubbles cannot float into, and preferably a couple inches from substrate.

high co2 and low/med light plus a rich dosing regime is a recipe for success. the reason you were noticing very fast growth in amazonia is probably because of the ammonia it leaches in the first couple of months, plants love that. in the first couple of months your plants had an abundance of N, from amazonia and K+ micros from your ferts, now that your substrate is starting to stop leaching, your tank is probably N-limited, which is why you're noticing slower plant growth.

so, my suggestions.
1. keep light low
2. co2, high
3. ferts, moderate (i'd recommend you swap to apt complete it should give you faster growth.)

 

[meyscapes]

Hi @MichaelJ,

Thank you for the welcome and for your reply! I’ve not heard of doing a PH profile before, so I’ll check that out - thanks for sharing.

I’ve attached three photos of how the tank is looking as of today and the last photo is the tank back in November.

I had to remove a lot of the tall background plants last weekend due to algae growth on them and being too tall for the tank.

I only changed the position of the drop checker today, but I think I need to adjust it still.

Thanks,

Melissa

 

[plantnoobdude]

Hi @MichaelJ,

Thank you for the welcome and for your reply! I’ve not heard of doing a PH profile before, so I’ll check that out - thanks for sharing.

I’ve attached three photos of how the tank is looking as of today and the last photo is the tank back in November.

I had to remove a lot of the tall background plants last weekend due to algae growth on them and being too tall for the tank.

I only changed the position of the drop checker today, but I think I need to adjust it still.

Thanks,

Melissa

drop checker looks a bit more on the blue side. i'd bump it up a touch. till it looks like this

 

[meyscapes]

Hi @plantnoobdude,

Thank you for your reply!

That’s interesting to hear, a lot of what I read today was saying that drop checkers aren’t very accurate as they show how much Co2 was in the water a couple of hours previous to the time that you’re viewing them. I only discovered about the positioning of them today, so I will adjust it. I didn’t realise it had to be in an area where Co2 bubbles can’t get into it. I use an inline diffuser, so there are often fine bubbles everywhere when the Co2 is on. I’ll have a look and see if I can readjust it, thanks for that tip!

That makes sense. This is my first time using ADA Amazonia and I did a dark start for a few weeks to avoid the largest amount of leeching that starts at the beginning. I wasn’t sure how long it lasts though overall, so haven’t known when to switch the ferts! I have APT complete so will make the switch over to this and see if it makes any difference.

I added some photos in another reply above btw to show the condition of the tank currently.

Thank you for the help!

 

[meyscapes]

drop checker looks a bit more on the blue side. i'd bump it up a touch. till it looks like this
View attachment 180325

Not sure if it would make much difference but I took the photo 4 hours after Co2 had turned off. The lighting in the photo is a bit funny as well as my living room light was on, which made the white walls behind the tank look purple/blue, so there’s a bit of a colour discrepancy 🤷🏻‍♀️ I keep an eye on the drop checker and usually it’s a light green. Thanks though!

 

[plantnoobdude]

That’s interesting to hear, a lot of what I read today was saying that drop checkers aren’t very accurate as they show how much Co2 was in the water a couple of hours previous to the time that you’re viewing them. I only discovered about the positioning of them today, so I will adjust it. I didn’t realise it had to be in an area where Co2 bubbles can’t get into it. I use an inline diffuser, so there are often fine bubbles everywhere when the Co2 is on. I’ll have a look and see if I can readjust it, thanks for that tip!

that is true, but it just means that you need to make sure the drop chcker is a nice green colour within an hour or two after the lights have been on. other than that i think drop checkers are more accurate, because methods that calculate co2 based on ph can be skewed by many other factors, such as new soil, kh swing from rocks leaching, wood, nitrification.

tank looks very nice!

 

[meyscapes]

that is true, but it just means that you need to make sure the drop chcker is a nice green colour within an hour or two after the lights have been on. other than that i think drop checkers are more accurate, because methods that calculate co2 based on ph can be skewed by many other factors, such as new soil, kh swing from rocks leaching, wood, nitrification.

tank looks very nice!

That’s true, the soil itself buffers my PH! I’ll see how the drop checker looks tomorrow now that it’s in a different position. I’ll probably do both tests and see they compare to each other. Hopefully once I get the co2 right, along with the nutrients the plants will pick up again 🤞🏼

And thank you! 😄

 

[meyscapes]

Just to update, I decided to test my nitrates and phosphates and it seems I have 30-40ppm of nitrates and 2-3ppm of phosphates.

I’m not too familiar with how many phosphates I should have vs nitrates…would this be considered too high overall?

 

[plantnoobdude]

Just to update, I decided to test my nitrates and phosphates and it seems I have 30-40ppm of nitrates and 2-3ppm of phosphates.

instead of hobbyist grade test kits, i'd look for a local water report

 

[meyscapes]

instead of hobbyist grade test kits, i'd look for a local water report

I use a mix of 60% RO and 40% tap water in my tanks, so it’s not all tap. I checked my local water report last week and couldn’t find phosphate levels on there, but there was 20ppm of nitrates.

 

[erwin123]

its important for the drop checker to be green and not turn yellow, but a drop checker can be 'green' and the CO2 levels could still be unstable. That's where pH measurement comes in.

 

[meyscapes]

its important for the drop checker to be green and not turn yellow, but a drop checker can be 'green' and the CO2 levels could still be unstable. That's where pH measurement comes in.

Yes that’s what I’m wondering. I’m going to try and get an idea of my PH profiling now after the suggestions and seeing other threads on here. Hopefully it’ll help me get a better idea of what’s going on in the tank and I can go from there, thanks!

 

[dw1305]

Hi all,

and couldn’t find phosphate levels on there

There is <"no legal limit for orthophosphate (PO4---) in tap water">, so the water companies don't report it (they can't be in breach of the limit, there isn't a limit).

All water companies add some PO4--- to their water for <"phosphate induced metal stabilisation">, (<"PIMS for control of "plumbosolvency">). Because you live in London your tap water is likely to <"contain enough PO4---"> to support some plant growth, but it may still be <"Liebig's limiting nutrient">.

<"Phosphate is a compound"> for which <"hobbiest test kits should be fairly accurate">, I haven't tried it but I think @jaypeecee has used the <"JBL low range test kit">.

cheers Darrel

 

[arcturus]

Hi @plantnoobdude,


That’s interesting to hear, a lot of what I read today was saying that drop checkers aren’t very accurate as they show how much Co2 was in the water a couple of hours previous to the time that you’re viewing them. I only discovered about the positioning of them today, so I will adjust it. I didn’t realise it had to be in an area where Co2 bubbles can’t get into it. I use an inline diffuser, so there are often fine bubbles everywhere when the Co2 is on. I’ll have a look and see if I can readjust it, thanks for that tip!

Yes, drop checkers do not show the real-time conditions of the tank and are quite sensitive to positioning. And, like any other colour based test, they are not easy to read. But they are much more accurate than ph/dKH tables. Despite all these limitations, they are the best tool you can use to gauge the CO2 levels. As several others suggested, do a pH profile (i.e. use a properly calibrated pH probe to (1) pH measure the pH of degassed water, (2) measure the pH of the tank water every hour or so, starting when before CO2 injection and the photoperiod starts, and until the end of the photoperiod).

 

[meyscapes]

Yes, drop checkers do not show the real-time conditions of the tank and are quite sensitive to positioning. And, like any other colour based test, they are not easy to read. But they are much more accurate than ph/dKH tables. Despite all these limitations, they are the best tool you can use to gauge the CO2 levels. As several others suggested, do a pH profile (i.e. use a properly calibrated pH probe to (1) pH measure the pH of degassed water, (2) measure the pH of the tank water every hour or so, starting when before CO2 injection and the photoperiod starts, and until the end of the photoperiod).

Thank you! This is what I’m doing today and I have a calibrated PH probe to check it with.

I’ll update this thread at the end of the day with the results.

 

[jaypeecee]

I haven't tried it but I think @jaypeecee has used the <"JBL low range test kit">.

Hi Everyone,

Yes, I have been a user of the JBL PO4 (phosphate) sensitive test kit for several years and this kit continues to serve me well. Now, that may sound like I don't replace expired reagents! Needless to say I do. The measurement range for this kit is <0.02 to 1.8 ppm.

JPC

 

[jaypeecee]

instead of hobbyist grade test kits, i'd look for a local water report

Hi @plantnoobdude

That's OK for knowing what's coming out of someone's tap. But it's not much good to an aquarist who wants to know what's in his/her tank. That's where a decent test kit is very helpful. And a water company test report will indicate minimum, mean and maximum values of water parameters. But, it will not indicate values for the moments when you need them. Furthermore, if I look at my water report for 2018, for example, and check out iron, the minimum was 3.00 micrograms/litre and the maximum was 253.00 micrograms/litre.

As Darrel (@dw1305) explains below, some parameters of interest to we aquarists are not available.

There is <"no legal limit for orthophosphate (PO4---)"> in tap water, so the water companies don't report it (they can't be in breach of the limit, there isn't a limit).

There are other examples of excluded water parameters that may be of importance to aquarists. I don't think silicon (as silicic acid) is included in water company reports.

JPC

 

[meyscapes]

Hi Everyone,

Yes, I have been a user of the JBL PO4 (phosphate) sensitive test kit for several years and this kit continues to serve me well. Now, that may sound like I don't replace expired reagents! Needless to say I do. The measurement range for this kit is <0.02 to 1.8 ppm.

JPC

Good to know! I’m quite new to testing phosphates and only tested them as I read about GSA appearing due to high level.

I’m not really sure what range is beneficial for plant growth vs too high or low. Same goes for nitrates! On the kits 40ppm comes at towards the high end, but I’ve read mixed info online, some saying this is fine, some saying this is too high.